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authorBabu Moger <babu.moger@amd.com>2018-06-13 21:18:22 -0400
committerEduardo Habkost <ehabkost@redhat.com>2018-06-22 15:01:15 -0300
commitf98bbd8304112187cafc3e636c31b2a3865d2717 (patch)
treed432efb88458ef55408c96786450b5d8cb5a3ec7
parent254790a909a2f153d689bfa7d8e8f0386cda870d (diff)
downloadfocaccia-qemu-f98bbd8304112187cafc3e636c31b2a3865d2717.tar.gz
focaccia-qemu-f98bbd8304112187cafc3e636c31b2a3865d2717.zip
i386: Allow TOPOEXT to be enabled on older kernels
Enabling TOPOEXT feature might cause compatibility issues if
older kernels does not set this feature. Lets set this feature
unconditionally.

Signed-off-by: Babu Moger <babu.moger@amd.com>
Message-Id: <1528939107-17193-2-git-send-email-babu.moger@amd.com>
[ehabkost: rewrite comment and commit message]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
-rw-r--r--target/i386/kvm.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 445e0e0b11..2d174f3a91 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -372,6 +372,13 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
         if (host_tsx_blacklisted()) {
             ret &= ~(CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_HLE);
         }
+    } else if (function == 0x80000001 && reg == R_ECX) {
+        /*
+         * It's safe to enable TOPOEXT even if it's not returned by
+         * GET_SUPPORTED_CPUID.  Unconditionally enabling TOPOEXT here allows
+         * us to keep CPU models including TOPOEXT runnable on older kernels.
+         */
+        ret |= CPUID_EXT3_TOPOEXT;
     } else if (function == 0x80000001 && reg == R_EDX) {
         /* On Intel, kvm returns cpuid according to the Intel spec,
          * so add missing bits according to the AMD spec: